This invention relates to the healing of bone fractures, non-unions and pseudoarthroses, and more particularly to the healing thereof by the application of ultrasound.
In the past 25 years or so, many researchers have investigated techniques for promoting the healing of bone defects in both human beings and animals. For example, the application of direct current, in the order of 20 microamperes, at the site of a fracture is known to promote bone growth and thus healing. The cathode is usually applied at the site of the defect; the anode is placed somewhere in the adjacent tissue or on the skin of the patient. While such arrangements are totally or partially invasive, non-invasive techniques are also in use; an externally generated electromagnetic field is caused to pass through the fracture site, thus inducing a current which promotes healing.
The first approach suffers from the disadvantage of being at least partially invasive, while the second suffers from the disadvantage of requiring precise alignment of coils relative to the area to be treated as well as constant attention of medical personnel. Another disadvantage of the electromagnetic technique is that treatment is required for 12-16 hours per day. Furthermore, many months are usually required to achieve healing when using any of the prior art methods.